Thin slabs of material are often inspected to determine thickness using known methods of observation and analysis of Fabry Perot interference fringes. In the case of a simple single slab of material, these known methods of inspection are based on the observation of interference fringes in an etalon formed by the parallel interfaces of the sample. However, when the thickness of a slab of material is greater than about 50 μm, employing these known methods to determine the thickness of the slab of material becomes difficult due to measurement noise resulting from Schott noise, thermal noise, or the presence of stray light, or some combination thereof. Therefore, these known methods have limited spectral resolution and are not effective when the thickness of a slab of material is greater than about 50 μm.
The subject matter claimed in this disclosure is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one example technology area where some embodiments described in this disclosure may be practiced.